A 60-GHz Variable Gain Amplifier with Phase-compensated Variable Attenuator

A 60-GHz variable-gain amplifier with a phase-compensated variable attenuator is proposed herein. The proposed circuit comprises a four-stage common-source amplifier and a phase-compensated attenuator. The proposed circuit is implemented using a 65-nm CMOS process and occupies 360 μm × 765 μm including pads. The measured peak gain is 15.2 dB, and the 3-dB bandwidth exceeds 17.5 GHz from 49.5 to over 67 GHz. In addition, the proposed circuit achieves a gain control range exceeding 14.7 dB within a 3-dB bandwidth. Owing to the proposed phase compensation technique, the phase-compensated attenuator exhibits a maximum phase error of 2.9° and a RMS phase error of 1.7° at 56 GHz while consuming only 11.8 mW of DC power.